musttest_game/mods/sulfur/init.lua

-- Localize for performance.
local math_floor = math.floor

minetest.register_node("sulfur:ore", {
  description = "Sulfur Ore",
  tiles = {"default_stone.png^technic_sulfur_mineral.png"},
  groups = utility.dig_groups("mineral"),
  drop = "sulfur:lump",
  sounds = default.node_sound_stone_defaults(),
	silverpick_drop = true,
})

minetest.register_craftitem("sulfur:lump", {
  description = "Sulfur Lump",
  inventory_image = "technic_sulfur_lump.png",
})

minetest.register_craftitem("sulfur:dust", {
  description = "Powdered Sulfur",
  inventory_image = "technic_sulfur_dust.png"
})

minetest.register_craft({
  type = "grinding",
  output = 'sulfur:dust 4',
  recipe = 'sulfur:lump',
})

minetest.register_craft({
  type = "anvil",
  output = 'sulfur:dust 2',
  recipe = 'sulfur:lump',
})

minetest.register_craft({
  type = "crushing",
  output = 'sulfur:dust 6',
  recipe = 'sulfur:lump',
	time = 60*1.5,
})



local c_lava = minetest.get_content_id("default:lava_source")
local c_lava_flowing = minetest.get_content_id("default:lava_flowing")
local c_stone = minetest.get_content_id("default:stone")
local c_sulfur = minetest.get_content_id("sulfur:ore")

-- Sulfur
local sulfur_buf = {}
local sulfur_noise= nil

local generate = function(minp, maxp, seed)
  -- Keep mapgen within bounds. Not in nether, not in shallow caves.
  if minp.y < -24000 or maxp.y > -256 then return end
	--minetest.chat_send_all("searching for lava")

  local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
  local a = VoxelArea:new{
    MinEdge = {x = emin.x, y = emin.y, z = emin.z},
    MaxEdge = {x = emax.x, y = emax.y, z = emax.z},
  }
  local data = vm:get_data(sulfur_buf)
  local pr = PseudoRandom(17 * minp.x + 42 * minp.y + 101 * minp.z)
  sulfur_noise = sulfur_noise or minetest.get_perlin(9876, 3, 0.5, 100)

	local max = math.max
	local min = math.min

  local grid_size = 5
  for x = minp.x + math_floor(grid_size / 2), maxp.x, grid_size do
  for y = minp.y + math_floor(grid_size / 2), maxp.y, grid_size do
  for z = minp.z + math_floor(grid_size / 2), maxp.z, grid_size do
    local c = data[a:index(x, y, z)]
    if (c == c_lava or c == c_lava_flowing) and sulfur_noise:get3d({x = x, y = z, z = z}) >= 0.2 then
			--minetest.chat_send_all("found lava")
      for xx = max(minp.x, x - grid_size), min(maxp.x, x + grid_size) do
      for yy = max(minp.y, y - grid_size), min(maxp.y, y + grid_size) do
      for zz = max(minp.z, z - grid_size), min(maxp.z, z + grid_size) do
        local i = a:index(xx, yy, zz)
        if data[i] == c_stone and pr:next(1, 10) <= 7 then
          data[i] = c_sulfur
        end
      end
      end
      end
    end
  end
  end
  end

  vm:set_data(data)
  vm:write_to_map()
end

minetest.register_on_generated(function(...) generate(...) end)